Question: addSelect of leftJoins in SelectQueryBuilder

Issue type:

[x] question [ ] bug report [ ] feature request [x] documentation issue

Database system/driver: [x] postgres

TypeORM version:

[ ] latest [ ] @next [x] 0.2.5 (or put your version here)

Steps to reproduce or a small repository showing the problem:

I am trying to build the following query:

SELECT 
	"skill"."id", 
	"skill"."categoryId",
	"categoryTranslation"."name" AS "category",
FROM skill "skill"
LEFT JOIN skill_category_translation "categoryTranslation"
	ON "categoryTranslation"."categoryId" = "skill"."categoryId"
	AND "categoryTranslation"."langCode" = 'de_DE'

using SelectQueryBuilder:

async findAll(langCode: string): Promise<Skill[]> {
    return await this.repository.createQueryBuilder('skill')
      .select('skill.id')
      .addSelect('skill.categoryId')
      .addSelect('categoryTranslation.name', 'category')
      .leftJoin(
        SkillCategoryTranslation,
        'categoryTranslation',
        'categoryTranslation.categoryId = skill.categoryId AND categoryTranslation.langCode = :langCode',
        { langCode },
      )
      .getMany();
}

but I get this query:

SELECT 
    "skill"."id" AS "skill_id",
    "skill"."categoryId" AS "skill_categoryId",
    "categoryTranslation"."name" AS "category",
    "categoryTranslation"."categoryId" AS "categoryTranslation_categoryId", 
    "categoryTranslation"."langCode" AS "categoryTranslation_langCode"
FROM "skill" "skill"
LEFT JOIN "skill_category_translation" "categoryTranslation"
    ON "categoryTranslation"."categoryId" = "skill"."categoryId" 
    AND "categoryTranslation"."langCode" = $1
-- PARAMETERS: ["de_DE"]

which doesn’t return any column from categoryTranslation and only the two from skill.

Any suggestions? I was looking into subQueries but it doesn’t seem to deliver the simplicity I need. Thanks a lot!

[anodynos]

On a more general note, I have a similar problem:

I add a virtual (i.e non existent field) such as .addSelect("'FOO'", "Table_alias_foo") and although I can see it in the SQL (and is returned properly when raw SQL is executed), it’s not returned in the resulted object with getMany(). In my specific case it’s a count(*) but FOO works well to demonstrate the issue.

The question is, can we include a custom field in the resulted object, using getMany (and not getRawMany which is not very useful)?

EDIT:

I found a workaround, by using a “virtual column” - it’s not very elegant and scaleable, but it works: Basically all you need is to have “foo” as a column in the model, ideally with the same type you intend to have, and omit it from being selected ie:

  @Column({ nullable: true, select: false })
  foo: number;

Essentially this creates a placeholder for getMany to know what to include in the object.

It would be great if there was an annotation for this usecase, eg @VirtualColumn that doesn’t actually generate the column in the db schema, but knows that it should be included in the returned object with getMany, if it’s part of the SQL result.

[mschuttt]

What’s the status on this one? I currently have the same problem… any workaround / fix?